Control valve system



May 27, 1969 M. A. TOWNSEND 3,446,225

CONTROL VALVE SYSTEM Filed Jan. 6, 1967 Sheet of 3 BLOWER HEAT EXCHANGER GOVERNOR GOVERNOR SPEED LIMITING INVENTOR.

MILES A. TOWNSEND BY u- 1% ATTORNEY,

May 27, 1969 TOWNSEND 3,446,225

CONTROL VALVE SYSTEM Filed Jan. 6, 1967 Sheet 3 of 3 FICLZ //VVENTOR-' MiLQS Q. Townsend.

J- .fLL... ATTORNEY May 27, M. OW

CONTROL VALVE SYSTEM Filed Jan. 6, 1967 Sheet 3 of 3 HEAT EXCHQNGER NIB 2? es 9.76m) send ,5. Juk- A TTO/QNE Y United States Patent Ofi ice 3,446,225 Patented May 27, 1969 3,446,225 CONTROL VALVE SYSTEM Miles A. Townsend, Rockford, Ill., assignor, by rnesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Jan. 6, 1967, Ser. No. 607,857 Int. Cl. F0111 25/06, 25/14; F01d 19/00 US. Cl. 137-28 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for regulating the speed of fluid driven prime movers, and more particularly to a hydraulic servo mechanism which supplements the governor controlled operation of a fluid driven prime mover.

The servo mechanism of this invention comprises a valve system which is arranged to supply high pressure hydraulic fluid for operating a servo device to permit normal governor speed control of the prime mover and to modify the governor speed control in accordance with variations in'bearing pressure of the prime mover.

It is among the objects of this invention to provide a hydraulic control valve system for fluid driven price movers, which operates through a speed limiting servo device to supplement the governing control of the prime mover.

Another object is to provide such a hydraulic control valve system which provides a constant regulated pressure supply over a wide range of discharge pressure.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein FIGURE 1 is a block diagram of the hydraulic servo mechanism of the invention applied to the fluid control valve of a prime mover.

FIGURE 2 is generally a vertical sectional view to show detailed structure of the valve system portion of FIGURE 1.

FIGURE 3 is an elevational view of the servo device of the invention with portions sectioned to show details.

In FIGURE 1, the potrion above the broken line represents a forced draft blower control system while the portion below the broken line represents the hydraulic servo mechanism of the invention. The forced draft blower control system comprises a steam turbine driven blower 10, a steam control valve 12, a governor 14 and a feed-back line 16 between the blower and governor for regulating the steam supply in accordance with the speed of the blower.

The hydraulic servo mechanism comprises a control valve unit 18 to which oil is supplied by line 20 and transmitted by lines 22 and 24 to a servo device 25 which is interposed between the valve unit 18 and steam control valve 12 and connected by line 26 with the control valve 12. A portion of the oil from the control valve unit 18 will also be directed by bearing oil line 27 to a heat exchanger 28 and the shaft bearings represented at B from which it is returned by line 29 to the valve unit 18.

Referring to FIGURE 2, the unit 18 consists of a metal block having a removable lower plate 18 which permits vertical cylindrical chambers 30, 32, 34, 36 and 38 to be cored from the block 18. The chamber 30 communicates by passageway 31 with chamber 32, chamber 32 communicates by passageway 33 with chamber 34, chamber 34 communicates by passageway 35 with chamber 36 and chamber 36 has a passageway 37 which communicates with bearing oil line 27.

Oil is supplied initially through line 20 to chamber 30 by pump 42 from a source, such as, a sump 44 and after passage through the valve unit, the servo and the bearings may be returned by transfer lines, not shown, to the source 44 for recirculation. The first oil stream in line 22 is transmitted directly to the servo device 25 from chamber 30 and the second oil stream in line 24 is transmitted from chamber 32 to the servo device 25. As will be explained later in connection with FIGURE 3, the stream 22 operates a pilot piston for servo 25 while the stream 24 operates the main servo piston of the servo 25. When the stream in line 24 is at desired operating pressure, the servo device 25 will be in normal operation and the control valve 12 of the blower system will be under the control of the governor 14.

As the oil moves through the valve unit 18 from chamber 32 to chamber 34 by passageway 33 and from chamber 34 to chamber 36 by passageway 35, the bearing oil stream is directed by the passageway 37 to the line 27 through the heat exchanger 28, the bearings B from which it is returned to chamber 32 by the line 29. Consequently pressure variations in the bearing oil in line 29 will affect the pressure in chamber 32 and also the operation of the steam valve 12. A branch line 52 communicates between bearing oil line 27 anad chamber 38 to provide pressure relief.

Each of the chambers 30, 32, 34, 36 and 38 has structures disposed therein which are operative to control oil flow through the valve unit 18 and maintain the flow of oil to the servo 25 and to the bearings B at desired pressures.

The valve structure in chamber 30 consists of a sleeve 60 which is frictionally positioned therein and has an orifice 62 which communicates with the passageway 31 through an adjacent cooperating communicating orifice 63. The sleeve 60 is provided with a tapered valve seat 64 below the orifice 62 and a valve plug 66 is normally biased against the seat '64 by spring 70 positioned in the lower portion 72 of the sleeve. The lower portion 72 of the sleeve is of reduced diameter providing a drainage zone 74 and has a plurality of apertures 76 which permits oil drainage when the valve plug 66 is moved from seat 64 by excess oil pressure in chamber 30. Adjusting means in the form of a nut and screw assembly 78 is provided for moving the sleeve 60 to position the orifice 62 relative to orifice 63 for controlling oil flow through passageway 31 to chamber 32.

The chamber 32 is provided with a fixed sleeve 80 forming an orifice 82 and has a coacting piston valve 84 with a leg 86 depending into the sleeve. The sleeve 80 is of a reduced diameter in its upper portion providing a drainage zone 88 and has an arrangement of upper and lower inner sleeves 90 and 92 as shown. The lower sleeve 92 provides a seat for a spring 94 which biases the piston valve 84 upwardly and also has a ball 95 disposed therein which is biased upwardly by a spring 96 against the leg 86 of the piston valve. The spring 96 is mounted on a pin 97 in a centrally apertured support 98 and is adjustable by means of nut and screw assembly 99 while the support 98 is positioned by a retaining spring 100 and forms a drainage zone 102 in the chamber 32.

The servo '25 will be in normal operation and permit the valve 12 to operate under the control of governor 14 so long as the oil stream in line 24 is at the desired high pressure. However, failure of the high pressure oil supply will operate through the servo to shut down the blower operation. Referring again to FIGURE 2, the bearing oil pressure in line 29 will maintain the piston valve -84 in position to close orifice 82 in the sleeve 80 until the bearing oil in line 29 drops sufiiciently to permit the force of high pressure oil in chamber 32 on ball 95 combined with the force of the spring load 96 to move the piston valve 84 upwardly and allow oil to pass through the orifice 82.

The chamber 34 is provided with a fixed sleeve 110 which has its upper portion spaced from the walls of the chamber providing an upper annular compartment 112 in communication with passageway 33 for receiving oil from chamber 32 and in communication with passageway 35 for supplying oil to chamber 36. The sleeve has spaced upper and lower orifices 114 and 116 and a coacting double valve plug 118 which is biased upwardly by spring 120 toward a plate and spring assembly 122 and provides a bearing oil pilot valve assembly. The spring 120 is mounted on an adjusting nut and screw assembly indicated at 124 and the sleeve 110 provides a drainage zone 126 at the lower end of the chamber 34. Orifice 116 communicates with chamber 36 through a pressure relief line 128 when the valve plug 118 moves downwardly under reduced oil pressure from line 33.

The chamber 36 is provided with a frictionally positioned sleeve 130 which is biased downwardly by spring 132 and has a balance piston 134 disposed in its upper end providing a bearing oil regulator valve assembly. The sleeve 130 forms an annular compartment 136 for oil from passageway 35 and the sleeve has an aperture 138 providing oil communication between the annular compartment 136 and the lower end of piston 134 while a stop 140 limits the downward movement of the sleeve 130. The annular compartment 136 communicates with the bearing oil pressure line 27 by way of the passageway 37 also by way of another passageway 142. Movement of the sleeve 130 downwardly will cut off the fiow through the passageway 37 and reduce pressure line 27.

The chamber 38 has a valve plug 150 frictionally positioned therein and biased upwardly by a spring 152 to provide a bearing oil pressure relief device. The valve plug provides an upper space with the upper end of chamber 38 and has an annular groove at its lower end to form an oil space 154 which communicates with the chamber 38 through a passageway 156.

The servo 25 of FIGURE 3 has a main piston 200 which is movable in cylinder 202 and has a mechanical connector 204 for operating the steam valve 12 of the blower unit. Oil is supplied by line 24 to the cylinder 202 to move the piston 200 upwardly against the biasing force of spring 206. A pilot valve, formed by pilot cylinder 208 and valve plug 214 communicates with the main cylinder 202, is apertured at 210 and 212 and receives a double valve plug 214 which controls oil flow into and out of the cylinder 202. A line 216 communicates with the sleeve through 212 for transmitting oil under pressure from the cylinder 202 to the top of piston 200 and the pilot cylinder 208 is provided with a lower aperture 218 permitting draining of oil. A compartment 220 is provided at the lower end of the pilot cylinder and communicates with oil line 22. A pilot piston 222 urges the valve plug 214 upwardly to a stop 224 while a spring 226 urges the valve plug 214 downwardly as the main piston 200 moves downwardly.

In operation, the main piston 200 of the servo 25 will be in the position of FIGURE 3 while the valve 12 of the blower supplies steam to the blower but the downward movement of the piston 200 cuts off the steam supply through the connector 204. The relative oil pressures in lines 22 and 24 will be such that the piston 200 will be positioned as in FIGURE 3 to permit the blower to be operated at rated or governor controlled speed until the operation of the turbine shaft causes the pressure of the bearing oil to vary. The resulting pressure change in line 29 will be effective to move the servo piston 200 down and shut off the steam supply to the valve 12 until the servo mechanism is reset for operation.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

I claim:

1. In a fluid motor system having a governor control for maintaining the speed of the motor shaft substantially constant, the combination which comprises,

(a) a servo device having a main cylinder mounting a piston therein and spring means for biasing the piston toward one end of the cylinder,

(b) a pilot cylinder extending from said one end of the main cylinder in communication therewith and a conduit communicating between the pilot cylinder and the opposite end of the main cylinder,

(c) a valve unit form of a plurality of tandem arranged chambers connected in series communication and having the first chamber in communication with an oil source,

((1) a first line for transmitting oil from said first of the tandem arranged chambers to said pilot cylinder,

(e) a second line for transmitting oil from the second of said tandem arranged chambers to said main cylinder,

(f) valve means in said second chamber for controlling the transmission of oil to the main cylinder and (g) a pilot valve having actuating means therefor in said pilot cylinder which is operative to transmit oil from said one end of the main cylinder to said opposite end of the main cylinder to move the main piston to move toward the opposite end of the main cylinder for releasing the governor control.

2. The combination as set forth in claim 1, further characterized by a third fluid line for distributing oil from a third chamber to the shaft bearings of the fluid motor and valve means for controlling the oil passage from the second chamber to said third fluid line.

3. The combination as set forth in claim 1, further characterized by valve means in the first chamber controlling the oil supply to the second chamber.

4. The combination as set forth in claim 3,, further characterized by other valve means in the first chamber 'which is operative to bypass oil transmission to the other chambers of the valve unit.

'5. The combination as set forth in claim 2, further characterized by said third fluid line being connected to the second chamber for transmitting oil from the motor shaft bearings for controlling the operation of the valve means in the second chamber.

6. The combination as set forth in claim 2, further characterized by said valve means being located in the third chamber and a fourth chamber.

7. The combination as set forth in claim 3, further characterized by a pressure relief valve in the third fluid line.

References Cited UNITED STATES PATENTS 1,816,020 7/1931 Meyer 137--28 NATHAN L. MINTZ, Primary Examiner. 

